Its True you can obviously see that its true
Answer: It mattered that Brutus was a patriot of a betrayer because he killed Caesar when Caesar trusted him. He back stabbed Caesar when Caesar thought of him of as a trustworthy friend.
I don't know if this is what you were looking for but I this is what I would put as an answer.
Answer:
to decrease bias
Explanation:
The experimental procedure stated in the question is a blinded placebo test. This procedure seeks to reduce the bias in the experiment due to the "placebo effect."
The placebo effect is the effect whereby patients treated with a placebo (a dummy treatment) claim to be responding better to treatment methods.